Geometrie und Kinematik der taiwanischen Inselbogen-Kontinent Kollision aus 3-dimensionaler Kartierung
Zusammenfassung der Projektergebnisse
In Taiwan two subduction zones come together in a quasi-orthogonal configuration. In the course of this project we successfully mapped the details of this 3-D configuration, focusing on several tectonic elements, in particular the Eurasia / Phillippine Sea plate boundary with its accretionary wedge/orogen complex, the Luzon volcanic arc and forearc, and the lithospheric-scale fold of the Eurasian lithosphere. We have produced accurate 3-D maps of the subducted EU and PSP slabs, of several major crustal faults (including the basal detachment of the Taiwan orogen), and of the EU plate tear (STEP fault) that controls southwestward migration of the subduction system. In terms of kinematics, we were able to define both long-term and short-term subduction rates of the EU slab. It became evident that the present-day convergence rate between EU and PSP (91 mm/yr) cannot be applied beyond about 2 Myr ago. This kinematics is consistent with geologic observations: from timing of opening of the southern Okinawa trough, to geometry of geologic boundaries within the Taiwan mountain belt, to geographic distribution, geochemical character, and timing of Quaternary volcanism in the Northern Taiwan Volcanic Zone. Even considering the complexity of the upper lithosphere, the overall 3-D kinematics of the plate boundary remains remarkably simple. The orthogonal trench-trench intersection is a kinematically stable one, which translates in a self-similar manner over time. No slab breakoff is required for the kinematics of the margin, and none is observed in geophysical or geological data. Changes in convergence rates may affect the speed at which the translation occurs, but not the basic geometry of the intersection. The outcome of this project has a significant impact on the understanding of both the local structure and tectonics of Taiwan, and of the more general plate tectonics of East Asia. It also advances the understanding of other arc-continent collision systems, past and present, which are considered as analogous to Taiwan.
Projektbezogene Publikationen (Auswahl)
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LITHOSPHERIC-SCALE AND UPPER-CRUSTAL-SCALE GEOMETRY AND KINEMATICS OF THE TAIWAN ARC-CONTINENT COLLISION. Geological Society of America Abstracts with Programs. Geological Society of America.
Carena, Sara; Suppe, John; Wu, Yih-Min & Kanda, Ravi V.S.
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MULTISCALE RETRODEFORMABLE TRANSECT OF THE ACTIVE TAIWAN ARC-CONTINENT COLLISION: STRATEGIES AND RESULTS. Geological Society of America Abstracts with Programs. Geological Society of America.
Hsieh, Yu-Huan; Suppe, John; Liu, Char-Shine; Huang, Hsin-Hua & Carena, Sara
